code: def _clean(self):
      mapper = self._actor.GetMapper()
      mapper.SetLookupTable(None)
      self._actor.SetMapper(None)
      self._actor = None
      self._polydata = None
      self._renderer = None
  
file_path: mne-python/mne/viz/_3d_overlay.py
imports: from collections import OrderedDict
  import numpy
  from ..utils import logger
label_desc: Use image node_id 9 for calling the _LayeredMesh obj's underlying member method code with example usage: obj._clean() without return types